Emil G. Klarman confirmed (Burger, A., "Medicinal Chemistry", second edition, page 1147, Interscience Publishers, Inc., New York, 1960) that there is no known cure for psoriasis, but "different therapeutic agents may produce involution of psoriatic lesions." Although occlusion of psoriatic lesions with an impermeable barrier is known to decrease the high mitotic rate of epidermal basal cells and to cause reformation of the granular cell layer (Fry, L., Almeyda, J., McMinn, R. M. H., "Effect of Plastic Occlusive Dressings on Psoriatic Epidermis", Br. J. Dermatol., 82, 458 to 462, 1970), patients with psoriasis, when applying adhesive tape, are warned "that its removal may traumatize the epidermis sufficiently to evoke an isomorphic lesion" (Van Scott, Eugene J. and Farber, Eugene M., "Dermatology in General Medicine," Chapter 8, page 226, McGraw-Hill Book Company, 1971).
Psoriasis affects about 2 percent of the American population. The great majority of these so affected have minimal skin involvement (less than 10 to 15 percent of the skin surface), which is still sufficient to produce severe physical discomfort and psychological effects in many patients (Weinstein, Gerald D., et al., "A Clinical Screening Program for Topical Chemotherapeutic Drugs in Psoriasis", Arch. Dermatol., Vol. 117, pp. 388,293, July, 1981). Their clinical testing involved application of test agents to psoriatic plaques under occlusion daily for up to nine days.
Williamson found that clearing of resistant plaques with anthralin was significantly enhanced by using an occlusive dressing (occluded for 12 hours daily with PVC film), but irritant side effects were increased (Coskey, Ralph J., "Dermatologic Therapy, December 1982, through November, 1982", Journal of the American Academy of Dermatology, Vol. 11, No. 1, pages 25 to 52, at 37, July, 1984). By instructing patients to cover nightly anthralin paste applications with semipermeable paper tape, a practical method for out-patient therapy was devised (Pearlman, Dale L., et al., "Paper-Tape Occlusion of Anthralin Paste", Arch. Dermatol, Vol. 120, No. 5, pp. 625-630, May, 1984).
An advertisement for Diprolene Ointment for treating psoriasis has a specific instruction not to use an occlusive dressing (Journal of the American Academy of Dermatology, Vol. 12, No. 4, 101A, April, 1985).
In a chaper on psoriasis, Arndt, Kenneth A. ("Manual of Dermatologic Therapeutics", third edition, pp. 143, Little, Brown and Company, 1983) states that overnight or 24-hour occlusive therapy with Cordran Tape will initiate involution in most lesions, and corticosteroids exert their beneficial effects in this setting as mitotic inhibitors. Although the same text points out undesirable effects from occlusive therapy (page 272), it asserts that occlusive (airtight) dressings increase the efficacy of cream preparations in treating psoriasis (page 274).
A medicated adhesive tape for treating psoriasis is being marketed. The "Physicians' Desk Reference" (PDR), 39th edition, page 897, 1985, provides the following information:
"Cordran Tape is a transparent, inconspicuous, plastic surgical tape, impervious to moisture. It contains . . . (flurandrenolide, Dista), a potent corticosteriod for topical use . . .
"Each square centimeter contains 4 mg of flurandrenolide uniformly distributed in the adhesive layer. The tape is made of a thin, matte-finish polyethylene film which is slightly elastic and highly flexible.
"The adhesive is a synthetic copolymer of acrylate ester and acrylic acid which is free from substances of plant origin. The pressure-sensitive adhesive surface is covered with a protective paper liner to permit handling and trimming before application . . .
"The tape serves as both a vehicle and an occlusive dressing. Retention of insensible perspiration by the tape results in hydration of the stratum corneum and improved diffusion of the medication. The skin is protected from scratching, rubbing, desiccation, and chemical irritation. The tape acts as a mechanical splint to fissured skin. Since it prevents removal fo the medication by washing or the rubbing action of clothing, the tape formulation provides a sustained action . . .
The directions for use state: "Replacement of the tape every twelve hours produces the lowest incidence of adverse reactions; but it may be left in place for twenty-four hours if it is well tolerated and adheres satisfactorily."